Cycling UK Forum

I've found to my horror a patch of rust on the top of the bottom bracket of my tourer. I'm guessing a chain coming off has damaged the paint slightly and water got in. I've scraped it back; some of it coming away in sheets ( !! ) and it extended around the diameter but not beyond the gear cable guides. I got it easily back to the raw metal so i've caught it early and treated it with Loctite 7503. What should I do next? I won't ride it until it is painted. It gets cleaned regularly with Muckoff and oiled. Having said that the bike is 30 years old, but much loved and cared for.

lead or zinc based primer/undercoat,spray.Spray topcoat,thin layers.It,ll be ok for the bottom bracket which always gets some stick.On my 60yr old frame,I,ve kept the original paint and daubed a rustproofer around the whole bottom bracket area,not pretty but effective.

I will restate Brucy's top tip of using Owatrol Oil to cheaply & easily keep a rusty frame in use without the expense & hassle of powder coating or respraying. You simply remove the worst of the rust & paint it on. It leaves a tough clear(ish) rust-resistant surface which you can paint over if you want. I have used it and while not the prettiest does the job, at least for the time being. The small tin goes a long way on a bicycle frame.

https://www.owatroldirect.co.uk/product/owatrol-oil/

Thanks
Can you buy lead based primers now?

If you can get back to good metal and want to patch-repaint, this stuff is excellent (smelly and to be handled with care, but excellent).

https://www.phoenix-paints.co.uk/produc ... /etch/pq23

The firm is a supplier of paints for model makers, but their enamels are super hard-wearing, and come in such a huge variety of colours that you will probably find a very close match somewhere in their list. Nice small tins, so you don’t end up buying gallons that you don’t need.

Geomannie: did the owatrol in your use remain feeling almost tacky when dry and has it proved scratch resistant?

( I did a test with owatrol on parts of an old frame . It still feels almost tacky even when clearly dry....now 18months to 2 years later. Perhaps not tacky....but can't easily run your hand over it...squeaky!. On one section I over sprayed the owatrol coat with a spray clear coat.....but it still doesn't feel like a nice smooth laquer finish)

It'll take a BB shell about 200 years to rust through.

hoogerbooger wrote: ↑22 Aug 2023, 9:17pm Geomannie: did the owatrol in your use remain feeling almost tacky when dry and has it proved scratch resistant?

( I did a test with owatrol on parts of an old frame . It still feels almost tacky even when clearly dry....now 18months to 2 years later. Perhaps not tacky....but can't easily run your hand over it...squeaky!. On one section I over sprayed the owatrol coat with a spray clear coat.....but it still doesn't feel like a nice smooth laquer finish)

I have used it for touching up one frame & substantially repainting another. In both cases it dried pretty much within 24 hours as I remember. The finish wasn't glossy hard like a smooth lacquer, but certainly not tacky. It's not a finish for your best bike but for covering up rust patches on a working bike it works fine for me.

I know Prescision Paints as I'm a modeller and have quite a few of their products. Their range used to be a lot more extensive before the present owners took them over. I need to buy some of their 2 part etch primer for something else. I've also found some paints called porcelaine paints.

I’ve noticed that the formulation of their enamels has changed in recent years. I had a break from using them for several years, then bought some for restoring old tinplate locos, and was astonished by how quick drying they now are at room temperature, almost too quick. I think their advice is to allow them to dry at 10 degrees, and I would take that seriously.

Visit your local Halfords and get a set of their 'stone chip & scratch repair system 3 pen kit': https://www.halfords.com/motoring/paint ... 25478.html

They do a fair range of different colours so hopefully will have something fairly close to what you're after. Being in the bottom bracket area it shouldn't be too visible so no need for a perfect match. I repainted an entire BB area a few years back and it's still in perfect condition after suffering similarly from light corrosion, probably caused by where the pump was seated and vibrating. The kit has everything you need and the primer smells suitably noxious!!

BromptonMarathonBWC wrote: ↑22 Aug 2023, 8:13pm Thanks
Can you buy lead based primers now?

What !You mean you don,t have shelves full of paint pots of indeterminate age? Shame on you. Never thought of that,probably not.

BromptonMarathonBWC wrote: ↑22 Aug 2023, 6:21pm I've found to my horror a patch of rust on the top of the bottom bracket of my tourer. I got it easily back to the raw metal so i've caught it early and treated it with Loctite 7503. What should I do next? I won't ride it until it is painted. It gets cleaned regularly with Muckoff and oiled.

Um... its just some rust. I tend just to rub in some old grease using an oily rag. Rust by its nature is porous so it should hold onto the grease very well and stop more rust from forming..
A quick wipe down with a greasy and oily rag once every month or two should be enough to see the frame through the next thirty years..

Take the rust off as best you can. Use Jennolite phosphoric acid to remove the rust and phosphate the steel. Prime and coat with paint. Works well.

Kurust is very useful for neutralising any last remaining traces of rust pitting. It's a water based emulsion that converts the rust to a stable organophosphate and acts as a primer when dry. It needs to be over painted for full protection.